Letoff control actuating means



' ril 23, 1957 Filed Nov. 22, 1955 c. v. CURRIN EIAL 2,789,421

LETOFF CONTROL ACTUATING MEANS 3 Sheets-Sheet 1 INVENTORS CHARBES V. CURRIN WALTER 7f PERKINS, J'R.

ATTORNEYS April 23, 1957 'c. v. CURRIN EI'AL LETOFF CONTROL ACTUATING MEANS 3 Sheets-Sheet 2 Filed Nov. 22, 1955 v INVENTQRS can/n5: v. cane/1v a I I L-- J k--- WALTER 7'. PERKINJLJ'R.

ATTORNE v.5

April 1957 c. v. CURRIN ETAL 2,789,421

LETOFF CONTROL ACTUATING MEANS 3 Sheets-Sheet 3 Filed NOV. 22, 1955 INVENTORS mamas r. cum?! 6 BY W41. rs? T. PERKINJJR.

ATTORNEYS United States Patent O 2,7 89,421 LETOFF CONTROL ACTUATING MEANS Charles V. Cnrrin and Walter T. Perkins, Jr., Wallace,

N. C., assignors to J. P. Stevens & Co., Inc., a corporation of Delaware Application November 22, 1955, Serial No. 548,369

2 Claims. (or. 66-86) This invention relates to letofi means for regulating the withdrawal of convolutely wound or spooled material, and more particularly to an improved actuating arrangement for such regulating means.

In copending application Serial No. 376,650, filed.

August 26, 1953, a letoff control mechanism is disclosed that incorporates an adjustable letoif drive and a planetary gear means responsive to the linear letoff speed for adjusting the letoif drive and thereby regulating the letoff speed; the particular form of this mechanism that is illustrated and described being arranged for use in warp knitting machines, and the planetary gear means being made responsive to the linear letofi' speed by a slave thread provided for this purpose.

The letotf control mechanism of the above noted copending application operates to excellent advantage in adjusting the letoif drive, but practical difiiculties have been encountered in using a slave thread for actuating the control adjustment satisfactorily because the slave thread must be wrapped at least once around the warp beam being controlled and it tends to become fouled with the adjacent threads or yarns being letofi from the beam.

According to the present invention the use of a slave thread is eliminated entirely, while still providing for actuation of the letolf control in direct relation to the linear letoif speed, by employing instead a follower roll disposed for riding the material being letoif, so as to be rotated by this material at the linear letotl speed, and connecting this follower roll so that its rotation actuates the adjusting means of the letoif control.

This actuating arrangement provided by the present invention is described in further detail below in connection with the accompanying drawings, in which:

Fig. 1 is a side elevation of a representative warp knit ting machine, partly broken away and omitting any illustration of the knitting means, but showing a letofi control actuating means arranged according to the present invention;

Fig. 2 is a fragmentary rear elevation (i. e., as seen from the left) of the warp knitting machine shown in Fig. 1;

Fig. 3 is a plan view of the follower roll arrangement;

Fig. 4 is a side elevation, partly in section, taken substantially at the line 4-4 in Fig. 1; and

Fig. 5 is a sectional detail taken substantially at the line 55 in Fig. 4.

The warp knitting machine illustrated in Fig. 1 is of a generally conventional form, the machine frame F being shown arranged to carry beams of warp knitting yarns at W and W, which may be made up in sections as shown in Fig. 2, and a cam shaft C being connected to rotate a drive shaft D from which the letoif motion of each warp beam W and W is driven separately through variable speed regulating devices R and R provided to make possible a compensating increase in beam speed so as to maintain a uniform linear letoff speed as the warp yarns are withdrawn for knitting.

2,789,421 Patented Apr. 23, 1957 Adjustment of the regulating devices R and R to maintain the letoif speed uniform is accomplished through a letofi control mechanism, which is designated generally in the drawings by the reference numeral 10, and which operates to compare the operating speed of the drive shaft D with the linear warp yarn letoif speed and to adjust the devices R and R from this comparison. For this purpose, the control device 10 is arranged with a first input, drive shaft at 12 and a second input drive shaft at 14, that is duplicated at 14' in correspondence with the number of warp beams W and W.

The first input drive shaft 12 is made responsive to the operating speed of the drive shaft D by means of a two stage sprocket chain connection as indicated at 16 and 18 in Fig. 2, and the second input drive shafts 14 and 14' are made comparably responsive (in a manner that is described in detail further below) to the linear letolf speed, so that the output of the control device 10 can be made to reflect changes in a comparison of these two inputs and to adjust the regulating devices R and R accordingly through suitable actuating linkages as indicated at L and L (compare Figs. 1 and 2). The previously noted copending application discloses in detail a mechanism that may be employed to particular advantage in the control device 10 for comparing the respective inputs and providing an adjusting output, and reference is made to that disclosure for further details in this respect.

The arrangement provided according to the present invention for making the input shafts 14 and 14' responsive to the linear letoff speed comprises follower 20 and Ztl are mounted on a standard 22 attached to the frame F and extending uprightly to carry pivot arm structures, based on pivot arms 24. and 24, in relation to the respective warp beams W and W.

These pivot arm structures are arranged with each pivot arm 24 and 24' thereof fitted at one end witha pivot hub (as seen best at 26 in Fig. 5) at which it is pivotally mounted on the standard 22, and in which a stub shaft 28 or 28' is axially mounted for rotation; and with each of the pivot arms 24 and 24' also formed with apertured bosses 30 and 30' spaced and aligned at their extending portions to receive extension rods 32 and 32' for sliding adjustment along the extending axis of each pivot arm structure to a proper reach with respect to each warp beams W and W, the bosses 30 and 30' each being fitted with set screws (as illustrated at 34 in Fig. 3) for fixing the extension rods 32 and 32 in place when adjusted.

The extension rods 32 and 32' are in turn fitted with retaining collars 36 and 36' that may be fixed in place by set screws (as shown at 38 in Fig. 3) at opposite sides of apertured bosses 40 and 40 spaced and aligned on mounting arms 42 and 42 to receive the extension rods 32 and 32' for disposition of the mounting arms 42 and 42' thereon for tilting transversely with respect to the extending axis of the pivot arm structures. The mounting arms 42 and 42' further have bearing hubs 44and 44' arranged thereon to complete the respective pivot arm structure and at which axle members 46 and 46 are journalled transversely with respect to the extending axis of the pivot arm structures to carry the follower rolls 20 and 20, each of which comprises a pair of roll bodies 48 and 48' formed of rubber or other suitable follower roll material and fixed on the axle members 46 and 46' in spaced relation at each side of the extending axis of the pivot arms 24 and 24.

On each axle member 46 and 46' there is also fixed a sprocket wheel 50 or 50' adjacent one of the roll bodies 48 or 48","withsprock'et chains 52 or 52' extending therefrom to sprocket wheels-54 or'54' fixed n thestub shafts" 28 or 28' at the pivot axes for the respective follower rolls. 20 and 20. Each of these stub shafts 28 and 28' also have .an additional sprocket wheel 56 01-56 fixed thereon fromfwhich further sprocket chain connections 58"01 58' exte'nd'xto the respective input shafts 14 or'14' of'the letofi control mechanism so as to connect the mechanismrlll for actuation from the rotation of the follower rolls and 20 'and thereby make it directly responsive to'the linear letofi speed inthe manner already explained above.

YTlie riding dispositionrof the follower rolls20' and 20' fors ensing the linear letoff speed is maintained during operation prirnarilyjby gravity, with the pivoted mounting'of the, followerroll's 20and'20' allowing adjustment forfthe'dir'ninishingdiameter of the yarn packages carried on the warp beams Wand W as yarn is Withdrawn therefrom for knitting. It" should also be noted, however', that the arrangement of the extension rods 32 "and 32' in the bosses 40and 40' of the bearing hub mounting arms 42 and 42' allows transverse tilting of the axle members 46 and 46', and thereby permits further adjustment of the individual follower roll bodies 48 and 481for riding contact to the best advantage at the warp beams W and W despite the unevenness that is normally present at the peripheral surface of yarn packages carried] thereon. In addition, the individual roll bodies 48' and 48"fare'further, arranged on the axle members 46 and146"withthe respective roll bodies 48 and 48' that are remote from the sprocket wheels 50 or 50'. spaced to.a greaterextentto the. side of the extending axisof thepivo't arms 24 or 24' for substantially balancing the riding weightyat each roll body 48 and 48'.

The .present invention has been described in detail to be: limited by this description .or otherwise except as defined in the appended. claims.

We claim:

1. Ina. letofixcontrolmechanism for a warp beam of.

a warp knitting machine or the like, the combination witlran adjustable warp beam letolf drive means and a control device for adjusting said drive means incorporating first and second input shafts one of which is driven in relation to the operating speed of said drive means, of means for driving the other of said input shafts in comparable relation to the linear letofi speed resulting from the operation of said drive means, said driving means for the other input shaft comprising a pivot arm structure;:anaxle-member journalled at the extending end'of said pivot arm structure for rotation about an axis disposed transversely with respect to the extending axis of said pivot armstructure and for tilting transversely with respect to said extending axis, a pair of rollbo'dies above for purposes of illustration only and is not intended fixed on said axle member and spaced at each side of the extending axis of said pivot arm structure for riding on said warp beam in contact with the material thereon that is being letoff under the control of said letotf mechanism so that said roll bodies are rotated by said material at the 'linear letofi speed, and connecting means causing the rotation of said roll bodies to drive said other input shaft.

2. In a letolf control mechanism, the structure defined in claim 1 and further characterized in that said connectingmeans comprises a sprocket wheelfixed on said axle memberadjacent one of said roll bodies," and a sprocket chain drive therefrom to said other input shaft, and in thatthe roll body remote from said sprocket wheelris spaced to a greater extent to the side of the extending axis ofsaid pivotarm structure for substantially balancing the riding weight of the respective roll bodies.

'ReferencesCited in the file of this patent UNITED STATES PATENTS 1,608,834 Bo'oth-et al. Nov. 30, 1926 2,470,125 Young May 17, 1949 2,489,609 Amidon Nov.'29, 1949 2,541,192- "Blake Feb. 13, 1951 2,600,256 Morrison et al. June 10, 1952 2,720,093 Lambach et a1. Oct. 11, 1955 

